a = 'hello'
print(len(a))

b = ' world'
print(a + b)

c1 = True
c2 = False
print(type(c1))
print(type(c2))

a = input('请输入第一个数：')
b = input('请输入第二个数：')
a = int(a)
b = int(b)
print(f'a + b = {a + b}')

